Solar heating systems are known wherein a fluid medium is heated from large solar panels and this heated fluid then passed in a heat exchanger to in turn heat water stored in a tank. A basic problem with all such systems is the risk of contamination of the heated water in the tank with the fluid medium transferring heat from the solar panels to the water. Thus, any corrosion in the heat exchanger itself might cause intermingling of this heated fluid with the water in the tank.
The problem is particularly aggravated when appropriate chemicals are added to the fluid medium to prevent corrosion of the solar panels themselves. Such toxic substances in the fluid medium should the same become intermingled with the water through corrosion of the heat exchanger or inadvertent leaks could be dangerous to persons using the heated water in the tank. Accordingly, it has been proposed to avoid the use of any toxic substances in the heated fluid used for heating the water and instead coat the solar panels with anti-corrosive chemicals. While this solution permits a toxic free fluid medium to be used in the heat transfer process and thus even sould a leak develop avoids seriously contaminating the stored water, the necessity of providing anti-corrosive coatings and anti-rust coatings on the various solar panels as well as other portions of the system can become prohibitive. If some appropriate safety arrangement could be provided to minimize the risk of contamination of the stored water in the storage tank by the heating fluid, then heating fluid with the necessary anti-corrosive chemicals and the like even though toxic could readily be used and the vast expense involved in providing specially treated coatings for the solar panels and other component parts wholly avoided.